Game Boy Color Zero (GBCZ) *With Build Guide Notes

[infinitLoop]

Hey everyone. I just closed up my Game Boy Color Zero, and wanted to show it off real quick. I have lots of pics of the build, so I will add those in additional comments (attachment limits and all), along with all the details on how it was set up, in edits. It actually turned out not to be too difficult in the end, what with Glitch'd Gaming's button board and Pocket Adventure's "Assist" boards, and so I hope other people give it a try.

I would have had it done a little sooner, but I dropped my first screen and cracked it - Luckily (!) it worked out, since, even though I had to wait a little while longer for the replacement, it actually was correct, where the first one had "touchscreen" functionality that added like a (precious...) mm or so, even though I did order it without that. Moral of the story - make sure you get that non-touch one!!

*** UPDATE ***

If you want to give this build a try, also check out my second attempt which has some 3D-printable brackets to make this much easier.

***

Highlights:

• 2.4in SPI Screen (with ~60fps - most of it is visible, but the left side is cut off a little, with overscan)

• "Safe" Shutdown on the power switch

• 2500mah battery =~ 5.5+ hours of gameplay

• Silicon shoulder buttons

• I2S Digital Audio with Digital Volume controls

• ADS-1115 Battery Monitor

• Full-size external USB port

• External SD Card access from original power switch spot

parts list

All the partsShow

• Pi Zero W

• 2500mah 3.7v battery (actually left-over from my very first GBZ build that I had to cannibalize)

• Aftermarket GBC shell with standard buttons from some rando AliExpress merchant

• GBP buttons for X/Y from Handheld Legend

• Button board from glitch'd gaming

• "Easy" button boards for shoulder buttons from kitsch-bent

• GBA Silicon for shoulder buttons also from kitsch-bent

• Clear screen guard from kitsch-bent

• 2.4in ILI9341 SPI Screen - the working one was from rando E-Bay

• Adafruit I2S Audio DAC and amp

• 23mm 8ohm 2w speaker

• SPI Adapter from pocketadventures

• Power Assist Basic, including Safe Shutdown, 5v boost, and recharge from pocketadventures

• ADS1X11 for battery monitoring (this one works with 1115 settings, even though I keep trying to get 1015s)

• UV LED light for front "power"

• Printed cartridge to hold Power Assist

• Printed X/Y GBP button wells

• Printed mounting hole (I needed to file it down some in spots, to fit with this build - If I do another, I think I would remix this to fit better with these builds)

• Short USB connector

• Power switch for a GB DMG (I had this for a little while, and don't remember where it came from, but most likely with HHLegend, RetroModding.com or Kitsch-Bent)

• "Clicky" tactiles for volume control

• Tiny DPDT switch for power-on, and safe shutdown/off, and to cut off battery from ADS

• PJ-328 audio jack (Although, if you can get one that fits the stock model, the button board would handle it better - this is just what I had on-hand, and it fit pretty good with the existing shell cut-outs for the standard one)

• 30awg silicon coated wire (perhaps the most important part in this list!)

• Custom designed screen border

software

how to set it upShow

• RetroPie 4.3 (because it's worked better for me than 4.4, with the SPI driver, for whatever reason)

• JUJ FBCP LCD Driver for SPI Display
  • detailed instructionsShow

    I discovered this method through VeteranGamer's posts, so this is cribbed from that mostly, but adapted to suit the orientation and overscan for this build.
    Here are the commands you will need to execute:

    Code: Select all

    git clone https://github.com/juj/fbcp-ili9341.git
    
    cd fbcp-ili9341; mkdir build; cd build
    
    cmake -DARMV6Z=ON -DILI9341=ON -DSPI_BUS_CLOCK_DIVISOR=6 -DGPIO_TFT_DATA_CONTROL=24 -DGPIO_TFT_RESET_PIN=25 -DSTATISTICS=0 ..
    
    make -j
    

    If you get an error that cmake isn't installed...Show

    I have never needed to install it here, but, you can run this to install it and then continue with the "cmake" line when it finishes:

    Code: Select all

    sudo apt-get install cmake

    Then add it to the startup process:

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    sudo nano /etc/rc.local

    Add this line somewhere above "exit 0":

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    /home/pi/fbcp-ili9341/build/fbcp-ili9341 &

    Here are the overscan settings I found work best.

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    sudo nano /boot/config.txt

    Paste these in, but make sure you do not have other conflicting settings for these in the config elsewhere. If you do, add a # to the beginning to disable them.

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    ##########################
    ### Small Screen Sizing ##
    ##########################
    framebuffer_width=284
    framebuffer_height=240
    
    ##########################
    ### Overscan Placement ###
    ##########################
    disable_overscan=1
    overscan_scale=1
    overscan_left=42
    overscan_right=2
    overscan_top=0
    overscan_bottom=0
    
    ##########################
    # Disable SPI
    ##########################
    dtparam=spi=off
    
    

• Adafruit (by way of Pimoroni) I2S Audio Amp
  • Install CommandShow

    Code: Select all

    curl -sS https://raw.githubusercontent.com/adafruit/Raspberry-Pi-Installer-Scripts/master/i2samp.sh | sudo bash

• RetroGame Controls
  • Mapping configShow

    Code: Select all

    sudo nano /boot/retrogame.cfg

    Code: Select all

    UP        22  # Joypad up
    DOWN       1  # Joypad down
    LEFT      23  # Joypad left
    RIGHT      0  # Joypad right
    ENTER     12  # 'Start' button
    SPACE      5  # 'Select' button
    A         16  # 'A' button
    B         14  # 'B' button
    X         26  # 'X' button
    Y          6  # 'Y' button
    L         20  # Left shoulder button
    R         15  # Right shoulder button
    ESC     12 5  # Hold Start+Select to exit ROM
    

• Minty Battery Monitor (Sixteenbit's fork) for battery monitor
  • Updating for ADS-1115Show

    Open up the script file:

    Code: Select all

    sudo nano ~/Mintybatterymonitor/MintyBatteryMonitor.py

    Find the line "adc = Adafruit_ADS1x15.ADS1015()" and update to "adc = Adafruit_ADS1x15.ADS1115()"
    
    Adn then scroll down to the convertVoltage method and update the line "voltage = float(sensorValue) * (4.09 / 2047.0)" to read "voltage = float(sensorValue) * (4.09 / 32767.0)"

• Safe Shutdown
  • detailed instructionsShow

    Getting the safe shutdown working was a bit of a challenge. PocketAdventures has some information over here. Unfortunately, some of it does not work out-of-the-box on older Raspian/RetroPie images.
    
    I was able to get it working using two methods.
    Both methods require an overlay added to startup, that should keep the "Signal On" to the PSU active, until the "poweroff" happens and sets it to low (cutting the power).

    Code: Select all

    dtoverlay=gpio-poweroff,gpiopin=4,active_low="y"

    Using Minty Battery Monitor / ShutdownShow

    I think this is the easier option, if using an ADS-1x15 for battery monitoring.
    Bring up the script:

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    cd ~;sudo nano Mintybatterymonitor/MintyShutdown.py

    Scroll to the bottom and update the Shutdown and Monitor buttons:

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    # Interrupts
    shutdown_btn = Button(17, hold_time=0.3)
    monitor_btn = Button(7, hold_time=2)
    shutdown_btn.when_held = shutdown
    monitor_btn.when_held = togglestate
    pause()

    I use 0.3 seconds for shutdown to try and improve the responsiveness, but any numeric value should work.

    Using config.txt with overlayShow

    The gpio-shutdown overlay needs to be installed on RetroPie 4.3, in order to call shutdown using config.txt. I found the instructions through here.
    
    First, get the overlay code:

    Code: Select all

    wget http://www.stderr.nl/static/files/Hardware/RaspberryPi/gpio-shutdown-overlay.dts

    Next compile it (you should be able to ignore any Warnings):

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    dtc -@ -I dts -O dtb -o gpio-shutdown.dtbo gpio-shutdown-overlay.dts

    Copy the command code to the overlay folder:

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    sudo cp gpio-shutdown.dtbo /boot/overlays/

    Finally, we need to add a uDev rule file for a power key:

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    sudo nano /etc/udev/rules.d/99-gpio-power.rules

    Paste in this code:

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    ACTION!="REMOVE", SUBSYSTEM=="input", KERNEL=="event*", SUBSYSTEMS=="platform", \
        DRIVERS=="gpio-keys", ATTRS{keys}=="116", TAG+="power-switch"

    And now we can register it in config:

    Code: Select all

    sudo nano /boot/config.txt

    Add in:

    Code: Select all

    dtoverlay=gpio-shutdown,gpio_pin=17

• Digital Volume
  • detailed instructionsShow

    Here's a little python script I hacked together for doing digital volume controls, since I wasn't able to find one on a (relatively short) google search-and-find. It's very basic - it doesn't log or provide any onscreen feedback. It just increases and decreases the volume when you hit one of two buttons (up and down). Props to HoolyHoo and all the other open-source scripters out there, for enough examples to pull this together pretty quickly:
    First, create the file:

    Code: Select all

    sudo nano volume.py

    You should have a blank text file. Paste the content in - if you used pins other than GPIO 13 for Up and 27 for Down, then change those near the top:

    here's the codeShow

    Code: Select all

    from gpiozero import Button
    from signal import pause
    import os
    
    # Location of perisitant state file
    statePath = "/home/pi/volume.txt"
    
    # Initial volume setting
    vState = 60
    # Minimum/maximum volume and how much each press adjusts
    vStep = 2
    vMin = 0
    vMax = 100
    
    # GPIO pin configuration
    volumeUpBtn = Button(13)
    volumeDownBtn = Button(27)
    
    
    # Functions
    def volumeDown():
        global vState
        vState = max(vMin, vState - vStep)
        os.system("amixer sset -q 'PCM' " + str(vState) + "%")
    
    
    def volumeUp():
        global vState
        vState = min(vMax, vState + vStep)
        os.system("amixer sset -q 'PCM' " + str(vState) + "%")
    
    
    def readData(filepath):
        with open(filepath, 'rb') as file:
            return file.read()
    
    
    def writeData(filepath):
        with open(filepath, 'wb') as file:
            file.write(str(vState))
    
    
    def doVolume():
        while True:
            if volumeUpBtn.is_pressed:
                volumeUp()
                writeData(statePath)
            elif volumeDownBtn.is_pressed:
                volumeDown()
                writeData(statePath)
    
    # Initial File Setup
    try:
        vState = int(readData(statePath))
        os.system("amixer sset -q 'PCM' " + str(vState) + "%")
    except:
        writeData(statePath)
        os.system("amixer sset -q 'PCM' " + str(vState) + "%")
    
    # Doin its thing
    volumeUpBtn.when_pressed = doVolume
    volumeDownBtn.when_pressed = doVolume
    pause()
    
    

    that will also create a file to store the current volume setting (to persist when you reboot) named volume.txt in the pi root.
    
    finally, you need to set it up to run the script at boot time:

    Code: Select all

    sudo nano /etc/rc.local

    Add a line above "exit 0" with this text:

    Code: Select all

    sudo python /home/pi/volume.py &

modifications

Things I had to changeShow

Screen notesShow

Although I actually discovered it on my own, it seems other people did as well around the same time - Since space is such a premium, the screen works best if you trim the case to fit. Luckily it's already a pretty good fit on the top and bottom, and the 2.4in screen fits nicely between the plastic wall where the power switch normally goes, and the LED indicator mounting spot. I trimmed the HDMI off the pi to fit better, because it was pushing against the screen at first, but that was when I had the touch-panel-installed one, and it might not have been necessary with the thinner, non-tft one.

I also ended up removing the connector on the SPI adapter board, and soldering its flat cable directly to the board, to save another mm or so.

Cuts madeShow

I ended up taking a bit more off the battery area, to more easily get the battery in and out of the shell, and I reinforced it a bit, in the rear of the battery compartment, just with some hot glue. I also ended up cutting a slit to that hole where the cartridge would be, so that I could work the wires into it that went to the power supply, mounted there.
Front shell cutouts and 1st battery cut. Mounted USB and volume buttons.:

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USB cut:

IMG_5341.jpg (553.96 KiB) Viewed 9938 times

X & Y Button WellsShow

The button board has built-in guide holes for drilling pilot holes, and then I used a step-up drill bit to get up to the proper size. I did try and work with the 8mm tactile mounting spots at first, but there just isn't enough room to get a button in there too. Maybe if someone comes up with a good 3D design to use on those it would work out.

I used Game Boy Pocket buttons, since they do not have the A/B printed into them, and I used a button well to match, and also the silicon from a GBP. It's important, if you do this, that you line up the slots on the wells with the silicon pad. they are pre-cut to fit in certain spots, so you won't get good action on the button if you don't. I also cut off the little hoop that would normally fit around a case peg, and that let it fit perfectly with the GBC silicon.

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Power SwitchShow

I moved the power switch up to the top, where it is on a Game Boy (and where the Color had an IR remote spot) so that I could use its switch spot for SD Card access (basically the same spot as the contrast slot on a GBZ).

I trimmed the little flap off of the switch, that would normally hold the game cartridge in place on a GB, and filed a little bit around the case in that area, and it fit pretty well. There is not a lot of give/take though, so you can see into the case some when it is switched to one side if it's not mounted just right. I used a very small DPDT (2P2T) switch so I could also cut the battery off from the ADS - the motion isn't very wide, but it works well and keeps the button pretty much within the cutout for it.

Another thing that I did, that worked well when the switch is too far to one side, is to use the flap that I trimmed off to cover up some of the opening, so that when the switch is to one side, you can't see into the case. But, I was able to position the switch just right so that it doesn't need it in there.

I also removed some of the area around where the lanyard would normally go, to mount the battery monitor toggle button there.

Power Supply and CartridgeShow

I ended up just using the onboard LEDs from the PSU for charging/charged/power, so I drilled the small holes in the print to expose those.

I also ended up cutting off the lower half of the cart model (just under where the PSU sits in it) to give that bit of space over to the battery to use.

finishing touches and optimization

ComingShow

• Coming

anyway, on to some pics...

Original Custom Screen GuardShow

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Closer shot of screen border/protectorShow

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Turned-on (upside down screen image)Show

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Opened up and exposedShow

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Back of the caseShow

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SD Card accessShow

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External USB and Volume controlShow

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Power Switch, Charging port, and Indicator LEDsShow

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[rodocop]

Nice to see something in a color shell. Good job!

[infinitLoop]

I did something somewhat unique for the shoulder buttons (although, who knows, someone else has probably done this before - someone has done everything, it seems - but it was an original thought for me anyway). it would be pretty easy to stick some tactiles in the sides there, but I've gotten spoiled on the silicon bounciness. So what I did was get some Game Boy Advance silicon, and some button pads, cut up the start/select and a/b pads, and glued them together and to a button board...

Shoulder buttons

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all the parts, cut upShow

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holes cutShow

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(I just eye-balled the hole placement, and tried to line it up with those little walls from the battery compartment)

glued togetherShow

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in the backShow

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at an angleShow

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[infinitLoop]

I will probably end up swapping the screen protector out at some point for a glass one, with just a stock whatever printed on it. Although I like the custom pi/zero aspect, the adhesive on the clear plastic lens is a little uneven, which makes it look like there are air bubbles in places on the printed vinyl sticker, so that's not ideal.

Here is the png I did for it though, if anyone else wants to use it or modify it (with and without "zero")

cuttin it upShow

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with the zero textShow

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[MrErickson]

Nice build, looks good!

[waffe]

Good job on the build! I like the powersupply, did not know about that one!

[infinitLoop]

Good job on the build! I like the powersupply, did not know about that one!

thanks!

it is very nice - i like it quite a lot! it's got a small power strip too, so if you only have 3 things to power (like say, pi, audio amp, and usb in this one), you don't even need another strip for that. and when you mount it in a cartridge, pretty much all the pins for wiring poke out from where the case ends too, which is very convenient (it will fit in just about any "hollow" cart model, but the one on the site has indented marks where the onboard LEDs are, and a hole for the charge port).

the only downsides are that you can't just power from the charge port, since it doesn't provide enough power to everything that way without a battery to give it a boost, and that it's not as powerful as helder's psu, so even though it works great for zero builds, i don't think it would work well with more hungry builds like a/b+ or other types of pis.

[infinitLoop]

Added detailed instructions for setting up Digital Volume controls and for configuring the screen

[infinitLoop]

a few more shots of the build...

here's another inside shot, with the battery tucked in

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from the back - battery accessShow

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bottom - headphone jackShow

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removed the SPI connectorShow

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(lifted a couple pins (again) but they weren't in-use, so it still worked)

screen soldered and taped to the boardShow

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[infinitLoop]

Here's how I hooked up the GPIO. I also added the retrogame config to the original post instructions

I used everything on there, except the 5vs and one ground...

Original GPIO Layout (Updated in later post)Show

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